1. Field of the Invention
The present invention relates to transmitting devices, reconstruction devices, transmitting methods and reconstruction methods for broadcasts with hidden subtitles.
2. Background Information
News reports about disasters or elections are typically broadcast with a subtitle image overlaid over an original image constituting the plain broadcast. This enables the viewer to obtain real-time information while viewing the program. However, there are cases in which a broadcast is temporarily recorded on a storage medium and viewed at a later time, so that the information that was useful at the time of the broadcast may not be useful anymore at the actual time of viewing.
JP 2000-41185A discloses a method for hiding unnecessary character information. FIG. 14 is a diagram illustrating the conventional character hiding method described in JP 2000-41185A. In FIG. 14, a partial image of the image corresponding to the character portion before the characters have been inserted is sent as a part of the transmitted bit string and overlayed on the receiving side. A code classification unit 1 separates the received signal into a main image over which the subtitles are overlaid and the partial image from before the subtitles have been overlaid, and outputs these images to a main image decoding unit 3 and a sub-image decoding unit 5. The main image decoding unit 3 and the sub-image decoding unit 5 decode the main image and the sub-image, respectively. Moreover, an operation unit 9 is operated by the viewer, and the viewer's operation is output from the operation unit 9 to a control unit 7. A superimposing unit 11 outputs an image based on a main image and a sub-image, in accordance with an instruction from the control unit 7. In this situation, if the viewer has entered an operation for outputting a main image, then the main image is output. If, on the other hand, the viewer has entered an operation for outputting the original image, then the main image and the sub-image are combined, and an image in which the subtitle portion has been overwritten is output.
With the configuration of JP 2000-41185A, in situations in which the reconstruction is performed after a temporary recording, if a digital recording is made, then it can be selected whether subtitles should appear or not appear during the reconstruction. However, in this case, the viewer needs to select one of those manually. That is to say, when reconstruction after temporarily storing, the viewer needs to explicitly know the current time, compare the current time with the time the content has been broadcast, and to manually set whether subtitles should be displayed or not. Moreover, the viewer cannot be aware of information with a time limit, such as information about a campaign with a time limit, so that it is difficult to turn the display of the information with the time limit on or off as intended by the broadcaster. Furthermore, recent storage media, such as DVD players, can store large amounts of data, and switching the display of subtitles for such large amounts of stored data on or off every time means poor operability for the viewer.
In view of the above, there exists a need for transmitting devices, reconstruction devices, transmitting methods and reconstruction methods for broadcasts with hidden subtitles which overcome the above mentioned problems in the prior art and which have good operability for the user. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.